QueryStrategy to allow querying routes based on Advertising Strategy

router/query.go

@@ -15,6 +15,8 @@ type QueryOptions struct {
 	Network string
 	// Router is router id
 	Router string
+	// Strategy is routing strategy
+	Strategy Strategy
 }
 
 // QueryService sets service to query
@@ -52,6 +54,13 @@ func QueryRouter(r string) QueryOption {
 	}
 }
 
+// QueryStrategy sets strategy to query
+func QueryStrategy(s Strategy) QueryOption {
+	return func(o *QueryOptions) {
+		o.Strategy = s
+	}
+}
+
 // NewQuery creates new query and returns it
 func NewQuery(opts ...QueryOption) QueryOptions {
 	// default options
@@ -61,6 +70,7 @@ func NewQuery(opts ...QueryOption) QueryOptions {
 		Gateway:  "*",
 		Network:  "*",
 		Router:   "*",
+		Strategy: AdvertiseAll,
 	}
 
 	for _, o := range opts {

router/router.go

@@ -146,6 +146,7 @@ type Advert struct {
 // Strategy is route advertisement strategy
 type Strategy int
 
+// TODO: remove the "Advertise" prefix from these
 const (
 	// AdvertiseAll advertises all routes to the network
 	AdvertiseAll Strategy = iota

router/table.go

@@ -135,7 +135,7 @@ func (t *table) List() ([]Route, error) {
 }
 
 // isMatch checks if the route matches given query options
-func isMatch(route Route, address, gateway, network, router string) bool {
+func isMatch(route Route, address, gateway, network, router string, strategy Strategy) bool {
 	// matches the values provided
 	match := func(a, b string) bool {
 		if a == "*" || a == b {
@@ -150,12 +150,20 @@ func isMatch(route Route, address, gateway, network, router string) bool {
 		b string
 	}
 
+	// by default assume we are querying all routes
+	link := "*"
+	// if AdvertiseLocal change the link query accordingly
+	if strategy == AdvertiseLocal {
+		link = "local"
+	}
+
 	// compare the following values
 	values := []compare{
 		{gateway, route.Gateway},
 		{network, route.Network},
 		{router, route.Router},
 		{address, route.Address},
+		{link, route.Link},
 	}
 
 	for _, v := range values {
@@ -169,13 +177,46 @@ func isMatch(route Route, address, gateway, network, router string) bool {
 }
 
 // findRoutes finds all the routes for given network and router and returns them
-func findRoutes(routes map[uint64]Route, address, gateway, network, router string) []Route {
-	var results []Route
+func findRoutes(routes map[uint64]Route, address, gateway, network, router string, strategy Strategy) []Route {
+	// routeMap stores the routes we're going to advertise
+	routeMap := make(map[string][]Route)
+
 	for _, route := range routes {
-		if isMatch(route, address, gateway, network, router) {
-			results = append(results, route)
+		if isMatch(route, address, gateway, network, router, strategy) {
+			// add matchihg route to the routeMap
+			routeKey := route.Service + "@" + route.Network
+			// append the first found route to routeMap
+			_, ok := routeMap[routeKey]
+			if !ok {
+				routeMap[routeKey] = append(routeMap[routeKey], route)
+				continue
+			}
+
+			// if AdvertiseAll, keep appending
+			if strategy == AdvertiseAll || strategy == AdvertiseLocal {
+				routeMap[routeKey] = append(routeMap[routeKey], route)
+				continue
+			}
+
+			// now we're going to find the best routes
+			if strategy == AdvertiseBest {
+				// if the current optimal route metric is higher than routing table route, replace it
+				if len(routeMap[routeKey]) > 0 {
+					// NOTE: we know that when AdvertiseBest is set, we only ever have one item in current
+					if routeMap[routeKey][0].Metric > route.Metric {
+						routeMap[routeKey][0] = route
+						continue
 					}
 				}
+			}
+		}
+	}
+
+	var results []Route
+	for _, route := range routeMap {
+		results = append(results, route...)
+	}
+
 	return results
 }
 
@@ -187,17 +228,24 @@ func (t *table) Query(q ...QueryOption) ([]Route, error) {
 	// create new query options
 	opts := NewQuery(q...)
 
+	// create a cwslicelist of query results
+	results := make([]Route, 0, len(t.routes))
+
+	// if No routes are queried, return early
+	if opts.Strategy == AdvertiseNone {
+		return results, nil
+	}
+
 	if opts.Service != "*" {
 		if _, ok := t.routes[opts.Service]; !ok {
 			return nil, ErrRouteNotFound
 		}
-		return findRoutes(t.routes[opts.Service], opts.Address, opts.Gateway, opts.Network, opts.Router), nil
+		return findRoutes(t.routes[opts.Service], opts.Address, opts.Gateway, opts.Network, opts.Router, opts.Strategy), nil
 	}
 
-	results := make([]Route, 0, len(t.routes))
 	// search through all destinations
 	for _, routes := range t.routes {
-		results = append(results, findRoutes(routes, opts.Address, opts.Gateway, opts.Network, opts.Router)...)
+		results = append(results, findRoutes(routes, opts.Address, opts.Gateway, opts.Network, opts.Router, opts.Strategy)...)
 	}
 
 	return results, nil

router/table_test.go

@@ -1,6 +1,9 @@
 package router
 
-import "testing"
+import (
+	"fmt"
+	"testing"
+)
 
 func testSetup() (*table, Route) {
 	table := newTable()
@@ -108,10 +111,10 @@ func TestList(t *testing.T) {
 func TestQuery(t *testing.T) {
 	table, route := testSetup()
 
-	svc := []string{"svc1", "svc2", "svc3"}
-	net := []string{"net1", "net2", "net1"}
-	gw := []string{"gw1", "gw2", "gw3"}
-	rtr := []string{"rtr1", "rt2", "rt3"}
+	svc := []string{"svc1", "svc2", "svc3", "svc1"}
+	net := []string{"net1", "net2", "net1", "net3"}
+	gw := []string{"gw1", "gw2", "gw3", "gw3"}
+	rtr := []string{"rtr1", "rt2", "rt3", "rtr3"}
 
 	for i := 0; i < len(svc); i++ {
 		route.Service = svc[i]
@@ -218,4 +221,70 @@ func TestQuery(t *testing.T) {
 	if len(routes) != 0 {
 		t.Errorf("incorrect number of routes returned. Expected: %d, found: %d", 0, len(routes))
 	}
+
+	// query NO routes
+	query = []QueryOption{
+		QueryGateway(gateway),
+		QueryNetwork(network),
+		QueryStrategy(AdvertiseNone),
+	}
+
+	routes, err = table.Query(query...)
+	if err != nil {
+		t.Errorf("error looking up routes: %s", err)
+	}
+
+	if len(routes) > 0 {
+		t.Errorf("incorrect number of routes returned. Expected: %d, found: %d", 0, len(routes))
+	}
+
+	// insert local routes to query
+	for i := 0; i < 2; i++ {
+		route.Link = "local"
+		route.Address = fmt.Sprintf("local.route.address-%d", i)
+		if err := table.Create(route); err != nil {
+			t.Errorf("error adding route: %s", err)
+		}
+	}
+
+	// query local routes
+	query = []QueryOption{
+		QueryGateway("*"),
+		QueryNetwork("*"),
+		QueryStrategy(AdvertiseLocal),
+	}
+
+	routes, err = table.Query(query...)
+	if err != nil {
+		t.Errorf("error looking up routes: %s", err)
+	}
+
+	if len(routes) != 2 {
+		t.Errorf("incorrect number of routes returned. Expected: %d, found: %d", 2, len(routes))
+	}
+
+	// add two different routes for svcX with different metric
+	for i := 0; i < 2; i++ {
+		route.Service = "svcX"
+		route.Address = fmt.Sprintf("svcX.route.address-%d", i)
+		route.Metric = int64(100 + i)
+		if err := table.Create(route); err != nil {
+			t.Errorf("error adding route: %s", err)
+		}
+	}
+
+	// query best routes for svcX
+	query = []QueryOption{
+		QueryService("svcX"),
+		QueryStrategy(AdvertiseBest),
+	}
+
+	routes, err = table.Query(query...)
+	if err != nil {
+		t.Errorf("error looking up routes: %s", err)
+	}
+
+	if len(routes) != 1 {
+		t.Errorf("incorrect number of routes returned. Expected: %d, found: %d", 1, len(routes))
+	}
 }